 public class Sun { 
  	public static void main(String []args){ 
	int a=sum(100); 
 		System.out.println(a); 
} 
 
	public static int sum(int n) { 
         if(n==1) 
          	 return 1; 
         int a=n+ sum(n-1); 
 		return a; 
	} 
}